Turn on the speaker, and press the M [Mode] button once. The Speaker should say "FM Mode" or "Radio Mode".

Connect a power lead to the charging port of the Speaker. You don't have to plug it into a charging source, the cable serves as the FM antenna.

Place the Speaker and cable in a place where you would get the best FM signals. Outside is preferred.

Press and hold the M button until the Speaker goes silent. The Speaker will briefly play the stations it detects. I would recommend waiting 30 seconds before checking the Speaker. When the Speaker is done, the Speaker will stay on the same station.

To switch between radio stations, press the Back or the Forward button. To Mute or Unmute the Speaker, press Play/Pause. To Adjust Volume, hold either the Back or Forward buttons.